This invention relates to an electrode for use in the alkaline storage battery and to a method for the manufacture thereof. More particularly, this invention relates to improvements in the anode for use in the alkaline storage battery.
In batteries of the type using iron-electrodes such as, for example, Edison battery, there have heretofore been used iron-electrodes which are prepared by filling nickel-made containers called "pockets" with iron powder, graphite powder and a small amount of mercury kneaded with a small amount of aqueous solution of potassium hydroxide. So far as a storage battery using such an iron-electrode is charged and discharged at a relatively low current density, collapse of the electrode rarely occurs. As the current density of charging and discharging increases, however, the iron-electrode collapses or the fragments detached from the iron-electrode give rise to a short circuit, with the result that the charge-discharge cycle of the storage battery is sharply shortened to impair the utility value of the battery.
In order for the iron-electrode to withstand high current density of charging and discharging, it is necessary to decrease the electric resistance as much as possible, increase the mechanical strength and heighten the porosity thereby enlarging the area of solid-liquid interface between the electrode and the electrolyte. Since the aforesaid electrode which has a nickel-made pocket filled with iron powder has limited room for possible improvement in performance, a sintered mass of iron powder in which metal materials for both current collection and reinforcement are imbedded is used as an electrode. Even when such sintered mass is used as an iron-electrode, it is required to have as high porosity as permissible in order that the storage battery may be charged and discharged at a high current density. The increase of porosity entails degradation of mechanical strength and possibility of collapse.
A primary object of this invention is to provide for the alkaline storage battery an electrode which has outstanding durability to high current density of charging and discharging and a method for the manufacture thereof.